Wind instruments are musical instruments that include a hollow tube body serving as a resonator. According to different sounding principles thereof, the wind instruments are divided into two major types, namely, brass instruments and woodwind instruments. A brass instrument produces sound when a player blows into a mouthpiece set at the end of the resonator to vibrate a column of air in the resonator. Some very common brass instruments include trumpets, French horns, trombones, euphoniums and baritones.
Please refer to FIG. 1. Any type of brass instrument generally includes a mouthpiece 10, a leadpipe 11, a mouthpipe 12, a valve section 13 and a bell 14. The mouthpiece 10 includes a funnel-shaped or bowl-shaped cup 101 and a tapered shank 102 extended into the leadpipe 11. The valve section 13 is located between the mouthpipe 12 and the bell 14 and generally includes three to six valves. In most cases, three or four valves are arranged in the valve section 13.
Conventionally, the leadpipe 11 for a brass instrument has an opening formed into a conical bore 111, a size of which is depending on the type of the musical instrument and is usually fixed for receiving a correspondingly sized shank 102 therein. Therefore, to play different brass instruments, a brass player has to own not only a number of brass instruments, but also a number of differently sized mouthpieces 10 to produce sound.
This means the brass player has to purchase different types of brass instrument as well as differently sized mouthpieces, and the cost thereof doubtlessly forms a considerable burden to the brass player. Some brass instruments have a leadpipe bore that can only receive a small-size mouthpiece. For a brass player who prefers to a large-size mouthpiece for playing the brass instruments, the use of a mouthpiece having the player's preferred size to play different brass instruments without being limited to the mouthpiece sizes specific to individual brass instruments would no doubt help the player to get adapted to different brass instruments more quickly.
In view that the conventional brass instruments respectively have a leadpipe that can be used with only one type of mouthpiece, it is desirable to develop a bore-variable leadpipe to allow easy change of the bore size of the leadpipe of a brass instrument, so as to overcome the drawback in the conventional leadpipe.